<i>Francisella</i>

Sjöstedt, Anders

doi:10.1002/9781118960608.gbm01215

Cited by 3 publications

(3 citation statements)

References 66 publications

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“…holarctica and it is generally considered as susceptible but less sensitive to F. tularensis subsp. holarctica (Sjöstedt, 2015 ). Although O. cuniculus was found to be naturally infected with F. tularensis subsp.…”

Section: Tularemia In Animalsmentioning

confidence: 99%

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Phylogenetic Lineages of Francisella tularensis in Animals

Pilo

2018

Front. Cell. Infect. Microbiol.

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Tularemia is a zoonotic disease caused by the facultative intracellular bacterium Francisella tularensis. This microorganism can infect a plethora of animal species and its ecology is particularly complex. Much research was performed to understand its biology but many questions are still open, especially concerning the life cycle of this bacterium in the environment related to physical and biological parameters. Numerous animals are major hosts of F. tularensis but precise reservoir species are not yet well defined. Moreover, the exact range of species susceptible to tularemia is not clear and is complicated by the differences in virulence and ecology observed among the subspecies of F. tularensis. Indeed, different life cycles in nature, including the animal species concerned, were previously described for F. tularensis subsp. tularensis and F. tularensis subsp. holarctica. Recently, molecular techniques showing adequate discrimination between strains were developed, leading to the possibility to investigate links between phylogenetic lineages and infection in animals. New perspectives in research are now possible thanks to the information available and the simplicity of the molecular procedures. Current studies are unfolding the evolution of F. tularensis and these developments will lead to the elucidation of geographical and ecological differences observed by veterinarians, microbiologists and conservation biologists. However, systematic, coordinated collection of data and extensive sampling are important to efficiently assemble the findings of future research.

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Section: Tularemia In Animalsmentioning

confidence: 99%

“…The biotype “EryR” is erythromycin resistant, the biotype “EryS” is erythromycin sensitive and the biotype “japonica” is able to ferment glycerol. Subsequently, the subspecies mediasiatica was isolated from Central Asia and the strains exhibited moderate virulence but fermented glycerol and citrulline (Sjöstedt, 2015 ).…”

Section: Introductionmentioning

confidence: 99%

Phylogenetic Lineages of Francisella tularensis in Animals

Pilo

2018

Front. Cell. Infect. Microbiol.

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“…However, absolute levels somewhat decreased thereafter, although still significantly increased compared to the responses of the PBMC obtained before vaccination. Antigenic cross-reactivity is unlikely to sustain the longevity since F. tularensis is not closely related to other human pathogens ( 25 ). Moreover, since tularemia is a rare disease in most regions of the world ( 26 ), reexposure is an unlikely reason for the extremely long-lived cell-mediated immunity and, therefore, the data support the notion that natural infection, or vaccination, may result in very long-lasting, persisting for many decades.…”

Section: Discussionmentioning

confidence: 99%

Analyses of human immune responses to Francisella tularensis identify correlates of protection

Lindgren,

Eneslätt,

Golovliov

et al. 2023

Front. Immunol.

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Francisella tularensis is the etiological agent of the potentially severe infection tularemia. An existing F: tularensis vaccine, the live vaccine strain (LVS), has been used to protect at-risk personnel, but it is not licensed in any country and it has limited efficacy. Therefore, there is a need of a new, efficacious vaccine. The aim of the study was to perform a detailed analysis of the characteristics of the human immune response to F. tularensis, since this will generate crucial knowledge required to develop new vaccine candidates. Nine individuals were administered the LVS vaccine and peripheral blood mononuclear cells (PBMC) were collected before and at four time points up to one year after vaccination. The properties of the PBMC were characterized by flow cytometry analysis of surface markers and intracellular cytokine staining. In addition, the cytokine content of supernatants from F. tularensis-infected PBMC cultures was determined and the protective properties of the supernatants investigated by adding them to cultures with infected monocyte-derived macrophages (MDM). Unlike before vaccination, PBMC collected at all four time points after vaccination demonstrated F. tularensis-specific cell proliferation, cytokine secretion and cytokine-expressing memory cells. A majority of 17 cytokines were secreted at higher levels by PBMC collected at all time points after vaccination than before vaccination. A discriminative analysis based on IFN-γ and IL-13 secretion correctly classified samples obtained before and after vaccination. Increased expression of IFN-γ, IL-2, and MIP-1β were observed at all time points after vaccination vs. before vaccination and the most significant changes occurred among the CD4 transient memory, CD8 effector memory, and CD8 transient memory T-cell populations. Growth restriction of the highly virulent F. tularensis strain SCHU S4 in MDM was conferred by supernatants and protection correlated to levels of IFN-γ, IL-2, TNF, and IL-17. The findings demonstrate that F. tularensis vaccination induces long-term T-cell reactivity, including TEM and TTM cell populations. Individual cytokine levels correlated with the degree of protection conferred by the supernatants. Identification of such memory T cells and effector mechanisms provide an improved understanding of the protective mechanisms against F. tularensis. mechanisms against F. tularensis.

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A llofrancisella

Qu¹,

Salam²,

Li³

2019

Bergey's Manual of Systematics of Archaea and Bacteria

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Al.lo.fran.ci.sel'la. Gr. adj. allos another, the other; N.L. fem. n. Francisella a bacterial generic name; N.L. fem. n. Allofrancisella the other Francisella referring to the fact that the genus is phylogenetically related to Francisella . Proteobacteria / Gammaproteobacteria / Thiotrichales / Francisellaceae / Allofrancisella Aerobic, nonmotile, coccobacilli, Gram‐negative, and nonspore forming cells. Catalase positive. Growth enhances by supplementation of cysteine. The identified polar lipid profiles consist of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylcholine. The respiratory quinone is ubiquinone‐8. The fatty acids in the cell membranes predominantly contain C 18:0 3‐OH, C 10:0 , C 18:1 ω9 c , and C 16:0 . DNA G + C content (mol%) : 30–33 (HPLC). Type species : Allofrancisella inopinata Qu, Li, Salam, Chen, Liu, Gu, et al. 2016, 4837 VP .

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Francisella

Cited by 3 publications

References 66 publications

Phylogenetic Lineages of Francisella tularensis in Animals

Phylogenetic Lineages of Francisella tularensis in Animals

Analyses of human immune responses to Francisella tularensis identify correlates of protection

A llofrancisella

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